E. Coli O157 Case Study

Introduction
The beef industry has been significantly impacted by the emergence of Shiga toxin-producing Escherichia coli (Callaway et al., 2013). Specifically, Shiga toxin-producing E. coli O157 is a foodborne pathogen of significant public health importance. It can cause mild to bloody diarrhea in humans which may progress to hemolytic uremic syndrome (Centers for Disease Control and Prevention, 1993; Hussein, 2007) that can be fatal in children, the elderly and immunocompromised individuals. E. coli O157 is also responsible for an estimated 63,153 illnesses, 2,138 hospitalizations and 20 deaths in the United States annually (Scallan et al., 2011). Cattle serve as a major reservoir of this pathogen (Gyles, 2007). The organism colonizes the hindgut of cattle and is shed in their feces which can contaminate
Subsequently, hides can serve as a main source of contamination of carcasses and beef products during processing (Arthur et al., 2008).
Laboratory methods used for the detection of E. coli O157 in cattle feces, on hides, and in beef products include traditional culture methods, immunological, and molecular based diagnostic methods (Barkocy-Gallagher et al., 2002; Deisingh and Thompson, 2004). The culture-based detection method exploits the specific biochemical characteristics of the pathogen for identification. It involves sample enrichment in a selective broth, followed by immunomagnetic bead separation, plating on selective agar medium, and confirmation of isolates by biochemical tests, agglutination, and/or PCR detection of serotype-specific and virulence genes (Bai et